CN109161794B - A kind of anti-delayed fracture high strength steel and preparation method thereof - Google Patents
A kind of anti-delayed fracture high strength steel and preparation method thereof Download PDFInfo
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- CN109161794B CN109161794B CN201811012468.7A CN201811012468A CN109161794B CN 109161794 B CN109161794 B CN 109161794B CN 201811012468 A CN201811012468 A CN 201811012468A CN 109161794 B CN109161794 B CN 109161794B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
Abstract
A kind of anti-delayed fracture high strength steel and preparation method thereof, belongs to technical field of alloy material.Chemical constituent mass content are as follows: C 0.35~0.45%, Si 0.25%~0.64%, Mn 0.30~0.90%, Cr 0.90~1.30%, Mo 0.25~0.45%, V 0.25~0.45%, Nb 0.02~0.06%, Cu 0.2~0.5%, Ni 0.2~1.0%, Als 0.02~0.05%, P≤0.015%, S≤0.010%, N≤0.005%, surplus Fe.The advantage is that steel delayed fracture stress ratio >=0.7 provided, yield strength >=1080MPa, tensile strength >=1200MPa are suitable for science of bridge building steel.
Description
Technical field
The invention belongs to technical field of alloy material, and in particular to a kind of anti-delayed fracture high strength steel and its preparation side
Method.
Background technique
Development of world economy promotes transportation and flourishes, and railway and highway are as main communications and transportation shape
Formula is also grown rapidly.During railway and highway construction, inevitably to build it is various across rivers, river, lake,
Extra large, paddy steel structure bridge, this just proposes more harsh requirement to the comprehensive performance of steel, in particular for steel structural bridge
The steel of beam need higher intensity, durability, corrosion resistance, lightweight and anti-delayed fracture performance.It is referred to above-mentioned
In properties, intensity and anti-delayed fracture performance are difficult to realize Synchronous lifting, limit the development of steel structure bridge.
Summary of the invention
The purpose of the present invention is to provide a kind of anti-delayed fracture high strength steel and preparation method thereof, steel provided by the invention
Material tensile strength reaches 1200MPa or more, and delayed fracture stress ratio reaches 0.7 or more, has weatherability, can be used for steel construction
Bolting steel in science of bridge building.
To achieve the goals above, the invention provides the following technical scheme:
A kind of anti-delayed fracture high strength steel, the component including following mass content: C 0.35~0.45%, Si
0.25%~0.64%, Mn 0.30~0.90%, Cr 0.90~1.30%, Mo 0.25~0.45%, V 0.25~
0.45%, Nb 0.02~0.06%, Cu 0.2~0.5%, Ni 0.2~1.0%, Als 0.02~0.05%, P≤
0.015%, S≤0.010%, N≤0.005%, remaining is Fe.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes C 0.35~0.45%, preferably
0.37~0.42%, more preferable 0.38~0.41%.The present invention improves the intensity and harden ability of steel using C element, passes through C member
The control of cellulose content realizes the intensity of steel and plasticity good fit.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Si 0.25%~0.64%, preferably
It is 0.27~0.60%, more preferably 0.30~0.57%.The present invention improves the anti-oxidant and sea water resistance of steel by Si element
Corrosive nature avoids Si from making steel can be used for preparing bolt the influence of steel cold heading performance by the control of Si constituent content
Equal components.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Mn 0.30~0.90%, preferably
0.35~0.80%, more preferably 0.40~0.75%.The present invention improves the harden ability and cold work hardening speed of steel using Mn
Rate is controlled by dosage, the segregation for avoiding Mn element from generating in steel process of setting, is reduced to steel cold plastic deformation not
Benefit influences.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Cr 0.90~1.30%, preferably
1.0~1.2%, more preferably 1.05~1.15%.The present invention improves harden ability, the wearability, corrosion resistance of steel using Cr
With elevated temperature strength performance；By controlling content, the influence to steel cold-forming property is avoided；In addition, Cr also can be reduced decarburizing tendency,
It can satisfy requirement of the bolting steel to heat treatment rear surface decarburization.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Mo 0.25~0.45%, preferably
0.28~0.42%, more preferably 0.30~0.40%.The present invention reduces steel to tempering using the hardenability of Mo element adjustment steel
Brittle sensibility, prevents steel from occurring temper brittleness after high tempering, to tension of the raising steel under high temperature tempered condition
Intensity has a significant impact, while being also beneficial to improve the anti-delayed fracture performance of steel.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes V 0.25~0.45%, preferably
0.27~0.42%, more preferably 0.30~0.40%.The present invention is analysed using V as carbide former in the high tempering stage
Tiny Carbide Precipitation phase out is conducive to the elevated temperature strength for improving steel；Vanadium carbide (VC) is typical hydrogen trap in steel, can
Protium in fixed steel, it is advantageous to the anti-delayed fracture performance for improving steel.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Nb 0.02~0.06%, preferably
0.03~0.04%.Nb and C are used cooperatively by the present invention, and NbC precipitated phase can be formed under the austenitic temperature of steel, are refined former difficult to understand
Family name's body crystal grain can make steel have excellent anti-delayed fracture performance and elevated temperature strength performance.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Cu 0.2~0.5%, preferably
0.25~0.4%, more preferably 0.3~0.4%.The present invention improves the weatherability of steel using Cu element, passes through control Cu member
The dosage of element, it is ensured that the cold-forming property of steel is unaffected.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Ni 0.2~1.0%, preferably
0.2~0.8%, more preferably 0.3~0.8%.The present invention improves the harden ability of steel, low-temperature flexibility and weather-proof using Ni element
Property, while cooperating the control of dosage, it is ensured that steel have excellent high tempering intensity.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes Als 0.02~0.05%, preferably
It is 0.03~0.04%.In the present invention, the Als indicates dissolved aluminum, and the present invention controls acid-soluble aluminum content in above range,
The harden ability of steel can be improved, while ensuring that the toughness of steel is unaffected.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes P, P≤0.012%, preferably
It is 0.005~0.01%.The present invention controls P element content in above range, and it is micro- to be avoided that P element is formed in solidification of molten steel
Segregation is seen, the delayed fracture sensibility of steel is reduced.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes S, S≤0.010%, preferably
It is 0.001~0.005%, more preferably 0.002~0.004%.The present invention controls S constituent content in above range, can keep away
Exempt from S element to be mingled with Mn formation MnS, reduces influence of the field trash to steel hot-working character.
In terms of mass content, anti-delayed fracture high strength steel provided by the invention includes N, N≤0.005%, preferably
It is≤0.004%.It reduces N content to avoid forming TiN field trash in steel, damages the toughness of steel.
Invention also provides the preparation method of anti-delayed fracture high strength steel described in above-mentioned technical proposal, including it is as follows
Step:
(1) molten steel including above-mentioned mass content component is provided, the molten steel is refined, molten steel is purified；So
Gained cleaning molten steel is successively cast, cooled down and stripped off the skin afterwards, obtains slab free of surface defects；
(2) it is kept the temperature after heating the slab of the step (1), is then successively rolled, sum aggregate of spinning volume, obtained
Wire rod；
The temperature of the heat preservation is 1200~1250 DEG C, and the time of the heat preservation is 120~240min；
The rolling includes roughing and finish rolling, and the temperature of the roughing is 1100~1200 DEG C, and the temperature of the finish rolling is
1000~1100 DEG C；
The temperature of the spinning is 880~950 DEG C；
The temperature of the collection volume is 500~550 DEG C；
(3) wire rod of the step (2) is successively quenched and is tempered, obtain anti-delayed fracture high strength steel；
The temperature of the quenching is 900~950 DEG C, and the soaking time of the quenching is 60~90min；
The temperature of the tempering is 600~650 DEG C, and the soaking time of the tempering is 60~120min.
The present invention provides the molten steel including above-mentioned mass content component, refines to the molten steel, is purified molten steel；
Then gained cleaning molten steel is successively cast, solidified and is stripped off the skin, obtain slab free of surface defects.The present invention is to the steel
The presentation mode of liquid does not have particular/special requirement, using well known to those skilled in the art.The present invention preferably mixes raw material, so
After melted, to obtain molten steel.The present invention does not have particular/special requirement to the raw material, is using well known to those skilled in the art
It can.In the present invention, described P, S and N are the impurity element in raw material, without being additionally provided.
The present invention does not have particular/special requirement to the hybrid mode of the raw material, using mixing side well known to those skilled in the art
Formula.After mixing, the present invention melts mixed material, obtains molten steel.The present invention does not have the temperature of the fusing
There is particular/special requirement, each raw material component can be made sufficiently to melt, obtains the uniform molten steel of component.In the present invention, the fusing
It is preferred that being carried out in converter.
After obtaining molten steel, the present invention refines the molten steel, to be purified molten steel.In the present invention, the essence
The temperature of refining is preferably 1515~1550 DEG C, and more preferably 1520~1540 DEG C；The time of the refining is preferably 30~
60min, more preferably 40~55min.The mode of refining of the present invention preferably includes vacuum refining, the vacuum refining when
Between preferably 20~30min, more preferably 25~28min；The pressure when vacuum refining is preferably those skilled in the art
Well known pressure；The temperature of the vacuum refining is preferably consistent with the temperature range of choice of above-mentioned refining.
After refining, the present invention is preferably passed through argon gas into the molten steel after the refining, to ensure that sour aluminum melting (Als) is refining
Homogenization in liquid, while the calcium-aluminate type impurity that Calcium treatment generates in refining process being promoted to float, avoid Al2O3Class folder
The sundries attachment mouth of a river causes dross problem of casting.In the present invention, the mode that is passed through of the argon gas is preferably led to from the bottom of ladle
Enter, the Argon pressure is preferably 0.5~1.2MPa, more preferably 0.6~0.9MPa.After being passed through argon gas, the present invention is preferably right
The molten steel for being passed through argon gas is de-gassed, and is purified molten steel.In the present invention, it is de- to preferably include vacuum for the mode of the degassing
Gas.The present invention does not have particular/special requirement to the specific embodiment of the vacuum outgas, using side well known to those skilled in the art
Formula.
After being purified molten steel, the cleaning molten steel is successively cast, cooled down and stripped off the skin by the present invention, obtains no surface
The slab of defect.In the present invention, the mode of the casting is preferably continuous casting, and more preferably low overheat is cast.In the present invention
In, the cleaning molten steel is cooled down by tundish, reaches the temperature of casting.In the present invention, the overheat of the tundish
Temperature is preferably 10~25 DEG C, and more preferably 15~20 DEG C.In the present invention, the temperature of the casting is preferably 1508~1523
DEG C, more preferably 1513~1518.
The present invention casts preferably by low overheat continuous metal cast process, realizes high pulling rate, reduces spill incident, improves slab
Inside and outside quality, while tapping temperature can also be reduced, improve furnace lining service life.When the casting mode is continuous casting,
Casting cycle is preferably 25~28min, more preferably 26~27min；Pulling rate is preferably 1.0~1.6m/min when casting, more excellent
It is selected as 1.2~1.5m/min.The present invention preferably casts under the above conditions, can reduce the center porosity of slab, shrinkage cavity and
Segregation inhibits column crystals growth, expands slab equiax crystal, and then improve the quality of slab；On the other hand it can make refining furnace and casting
Machine matching, improves equipment operating efficiency, extends the service life of equipment.
The present invention does not have particular/special requirement to the size of the slab, using well known to those skilled in the art.At this
In inventive embodiments, the size of the slab is 180 × 180mm square billet.The present invention does not have the specific embodiment of the casting
There is particular/special requirement, using well known to those skilled in the art.
After obtaining slab, the slab is successively cooled down and is stripped off the skin by the present invention, obtains slab free of surface defects.In
In the present invention, the cooling carries out preferably in burial pit；The time of the cooling is preferably 45~50h, more preferably 48~
50h.In the present invention, the outlet temperature of the slab cooling preferably≤300 DEG C, more preferably≤100 DEG C.
After cooling, the present invention strips off the skin to slab after cooling, removes the oxide skin and micro-crack of casting billet surface, obtains
Slab free of surface defects.The present invention does not have particular/special requirement to the specific embodiment to strip off the skin, using those skilled in the art
Mode known to member.
After obtaining slab free of surface defects, the present invention is kept the temperature after heating to the slab, is then successively rolled
System, spinning sum aggregate volume, obtain wire rod.In the present invention, the temperature of the heat preservation be 1200~1250 DEG C, preferably 1210~
1245℃；The time of the heat preservation is 120-240min, more preferably 150-180min.The present invention heats the slab laggard
Row heat preservation, can eliminate the mixed crystal phenomenon in slab, be dissolved coarse carbide in slab all.
After heat preservation, the present invention rolls the steel billet after the heat preservation.In the present invention, it is described rolling include roughing and
Finish rolling, the temperature of the roughing are 1100~1200 DEG C, preferably 1120~1180 DEG C, more preferably 1135~1175 DEG C.This
Invention is by the temperature setting of roughing in above range, and the steel billet after can making heat preservation recrystallizes, and then it is brilliant to refine original austenite
Grain.In the present invention, deflection sectional dimension of steel billet and before rolling in terms of the ratio between steel billet sectional dimension after rolling, steel after roughing
The deflection of base is preferably 50~60%, and more preferably 52~56%；After roughing, the present invention carries out the steel billet after the roughing
Cooling, temperature needed for reaching finish rolling.In the present invention, the temperature of the finish rolling be 1000~1100 DEG C, preferably 1025~
1080 DEG C, more preferably 1030~1075 DEG C.By the temperature setting of finish rolling in above range, the steel billet after making roughing exists the present invention
Lower than rolling under conditions of recrystallization temperature, flattening austenite grain can get, so that Post isothermal treatment process is further
Refine original austenite grain.In the present invention, the section deformation amount of steel billet is preferably 40~50% after finish rolling, more preferably 42~
46%；The present invention is preferably by the deformation amount controlling of roughing and finish rolling in above range, it is ensured that steel billet is abundant in rough rolling process
Recrystallization softening crystal grain obtains flat austenite structure in finishing stands, the tissue by subsequent Q-tempering can get 5~
8 μm of superfine grained structures.
After finish rolling, the steel billet after finish rolling is preferably carried out Water cooling by the present invention, in order to carry out next step spinning.At this
In invention, the outlet temperature of the Water cooling and the temperature of spinning are consistent.In the present invention, the temperature of the spinning is 880
~950 DEG C, preferably 890~940 DEG C, more preferably 900~935 DEG C.The present invention is spun under the above conditions, so that smart
Steel crystal grain after rolling further reduces.
After spinning, the steel after spinning are preferably entered cold bed by the present invention, are carried out slow cooling, are obtained wire rod；The slow cooling it is cold
But speed is preferably 5~10 DEG C/s, more preferably 6~9 DEG C/s；The mode of the slow cooling preferably includes air-cooled.In the present invention,
After spinning steel cooling outlet temperature it is consistent with winding temperature, the winding temperature be 500~550 DEG C, preferably 510~
545 DEG C, more preferably 515~540 DEG C.The present invention carries out collection volume under the above conditions, V element in the steel after being avoided that spinning
The precipitation of journey is licked in collection, and makes V element in the precipitation of follow-up heat treatment process, to obtain sufficient precipitating reinforcing effect.
After obtaining wire rod, the wire rod is quenched and is tempered by the present invention.In the present invention, the temperature of the quenching is
900~950 DEG C, preferably 905~945 DEG C, more preferably 910~940 DEG C；The soaking time of the quenching is 60~90min,
Preferably 65~85min, more preferably 70~80min.
In the present invention, the temperature of the quenching preferably passes through heating and reaches, and the rate of the heating is preferably 5~10
DEG C/min, more preferably 7~9 DEG C/min.After quenching, present invention preferably employs the cold mode of oil is cold to the progress of quenched steel
But.After quenching, the present invention carries out tempering to the quenched steel.In the present invention, the tempering and quenching
The interval time of processing is preferably 1.5~2.5h, more preferably 2h；The temperature of the tempering be 600~650 DEG C, preferably 605
~645 DEG C, more preferably 610~640 DEG C；The soaking time of the tempering be 60~120min, preferably 65~100min, more
Preferably 70~90min.In the present invention, the rate for being warming up to the tempering temperature is preferably 5~10 DEG C/min, more preferably
7~9 DEG C/min.After tempering heat preservation, the steel after tempering heat preservation are preferably cooled to room temperature by the present invention, and the mode of the cooling is excellent
It is selected as air-cooled.
The crystal grain of anti-delayed fracture high strength steel of the present invention is tiny, having a size of 5~8 μm, is conducive in high-intensitive item
Still there is preferable anti-delayed fracture performance under part.Anti-delayed fracture high strength steel of the present invention has excellent tension strong
Degree, yield strength, anti-delayed fracture performance and corrosion resistance, the yield strength >=1080MPa, the tensile strength >=
1200MPa, delayed fracture stress ratio >=0.7, corrosion resistance index >=6.5 are suitable for science of bridge building steel.
Detailed description of the invention
The metallographic microscope of 1 gained anti-delayed fracture high strength steel of Fig. 1 embodiment of the present invention.
Fig. 2 is the relational graph of Nb content and grain size in steel of the present invention.
Fig. 3 is the relational graph of grain size and delayed fracture stress ratio in steel of the present invention.
Fig. 4 is tempering temperature of the present invention and the relational graph that VC mass percent is precipitated.
Fig. 5 is the relational graph of VC mass percent and delayed fracture stress ratio in steel of the present invention.
Specific embodiment
The present invention provides a kind of anti-delayed fracture high strength steel and preparation method thereof, the group including following mass content
Point: C 0.35~0.45%, Si 0.25%~0.64%, Mn 0.30~0.90%, Cr 0.90~1.30%, Mo 0.25~
0.45%, V 0.25~0.45, Nb 0.02~0.06%, Cu 0.2~0.5%, Ni 0.2~1.0%, Als 0.02~
0.05%, P≤0.015%, S≤0.010%, N≤0.005%, remaining is Fe.
In order to further illustrate the present invention, high-strength to anti-delayed fracture provided by the invention with reference to the accompanying drawings and examples
Degree steel and its preparation method and application is described in detail, but they cannot be interpreted as to the limit to the scope of the present invention
It is fixed.
Embodiment 1
According to 1 scheme I dosage preparation raw material of table, surplus Fe is not listed in table 1.After raw material is mixed in converter
Fusing, obtains molten steel；Then molten steel is refined in LF furnace, after refining, is passed through argon gas from ladle bottom, Argon pressure is
0.6MPa, so that molten steel flow inclusion floating.Then under conditions of 67Pa, vacuum outgas 10min infuses molten steel after degassing
Enter tundish molten steel, cast at 15 DEG C of the degree of superheat, then gained slab is cooled down to 48h in burial pit, after cooling
Slab strip off the skin, obtain the slab of non-scale and crackle.
Slab is heated to 1200 DEG C, then keeps the temperature 160min, roughing is directly carried out after coming out of the stove, cross-sectional area deflection is
50%, by water-cooled cooling to 1000 DEG C of progress finish rolling, controlling cross-sectional deformation amount is 40%, after finish rolling steel Water cooling into
Enter Laying head, spin at 900 DEG C, control cooling velocity is 5 DEG C/s, carries out collection volume when temperature is reduced to 550 DEG C, obtains line
Material.
It by wire rod wire rod at 900 DEG C, keeps the temperature 60min and is tempered after oil is cold at 600 DEG C, keep the temperature 120min, it is air-cooled
The final performance of anti-delayed fracture high strength steel is obtained afterwards.
Embodiment 2~18
Anti-delayed fracture high strength steel is prepared according to the method for embodiment 1, and wherein the dosage of embodiment 2,3,10~12 is pressed
It is prepared according to scheme I, the dosage of embodiment 4~6 and 13~15 is prepared according to scheme II, and the dosage of embodiment 7~9 and 16~18 is pressed
It is prepared according to scheme III.Each embodiment specific process parameter is shown in Table 2.
Comparative example 1~6
1~6 dosage of each component of comparative example is shown in Table 1 scheme IV, requires to smelt according to GB/T 6478-2001, specific to prepare
Technological parameter is shown in Table 2.
Performance characterization and result
It is characterized, is tied using grain structure of the electron microscope to 1~18 gained anti-delayed fracture high-strength steel of embodiment
Fruit is as shown in Figure 1.Fig. 1 is the metallographic microscope of 1 gained steel sample of embodiment, as shown in Figure 1, the crystal grain of steel sample obtained by the present embodiment
Even tissue, tiny, average grain diameter is 5 μm.Other embodiments test result is close with embodiment 1, and specific test result is shown in Table
3。
According to 1~6 gained of " GB/T228 metal material tensile testing at ambient temperature " testing example 1~18 and comparative example
Tensile strength, yield strength, notch tensile limit stress and the critical intensity of steel, then according to σc/σNComputing relay fracture strength
Than for commenting the anti-delayed fracture performance of steel.The value of delayed fracture stress ratio shows test specimens between 0~1, close to 1
The anti-delayed fracture performance of product is preferable.Test result and calculated result are shown in Table 3.
According to following predictor formula, the corrosion resistance of embodiment 1~18 and 1~6 gained steel of comparative example: I=is calculated
26.01 (%Cu)+3.88 (%Ni)+1.20 (%Cr)+1.49 (%Si)+17.28 (%P) -7.29 (%Cu) (%Ni) -9.10
(%Ni) (%P) -33.39 (%Cu)2, calculated result is shown in Table 3.
According to GB/T 19746-2005 standard analog naval air environment, to 1~6 gained of embodiment 1~18 and comparative example
Steel carries out alternate-immersion experiment, specific experimental condition: etchant solution is the NaCI solution of mass fraction 3.5%, liquid bath temperature
Degree: 25 ± 2 DEG C, relative humidity: 60%-80%RH, cycle period 60min, wherein infiltrating time 10min, test period are
5,10,15 and 20 days, test result was shown in Table 3.The size of microcrystal of test institute and the Nb content of each embodiment are depicted as curve, ground
Study carefully influence of the Nb content to size of microcrystal, as a result as shown in Figure 2.As shown in Figure 2, in institute's research range, Nb content is higher, institute
The size of microcrystal for obtaining steel sample is smaller, therefore, it is advantageous to steel sample size of microcrystal is reduced to increase Nb content.
Each embodiment is tested into gained size of microcrystal and steel sample delayed fracture strength is depicted as curve, studies size of microcrystal
Influence to steel sample delayed fracture strength performance, as a result as shown in Figure 3.From the figure 3, it may be seen that size of microcrystal is smaller, steel sample
Strength character is higher, therefore, it is advantageous to the delayed fracture strength performance for improving steel sample to reduce size of microcrystal.
Using the content of VC in 1~18 gained steel sample of Phase Analysis Method testing example, and draw VC content and tempering
Temperature curve, as a result as shown in Figure 4.As shown in Figure 4, in institute's research range, tempering temperature is higher, and VC amount of precipitation is got over
Therefore height it is advantageous to VC amount of precipitation is improved to improve tempering temperature.
VC amount of precipitation in each embodiment and delayed fracture strength stress ratio are depicted as curve, study VC amount of precipitation to steel sample
The influence of product delayed fracture strength performance, as a result as shown in Figure 5.As shown in Figure 5, in institute's research range, VC amount of precipitation is more,
The promotion of steel sample delayed fracture property is more obvious, and therefore, improves VC amount of precipitation, and to improving, steel sample delayed fracture property is advantageous.
The chemical composition (mass content) of 1 embodiment 1~18 of table and 1~6 steel of comparative example
2 embodiment 1~18 of table and 1~6 technological parameter of comparative example
The performance test results of 1~6 gained steel of 3 embodiment 1~18 of table and comparative example
By the test result of table 3 it is found that within the scope of steel product provided by the invention tensile strength >=1200MPa, with conduct
The 42CrMo steel of comparative example is compared, and intensity obviously increases；And steel delayed fracture stress ratio provided by the invention reach 0.7 with
On, delayed fracture resistance is able to satisfy demand of the science of bridge building to steel；In addition, the corrosion resistance of steel provided by the invention also has
Be obviously improved, year reduction be reduced to 1.7mm or less.
By above embodiments and comparative example it is found that anti-delayed fracture high strength steel provided by the invention has excellent intensity
Performance and anti-delayed fracture performance can satisfy dimensions in the weather-proof bolt of high-intensitive anti-delayed fracture of M5-48mm range
Use intensity requirement.
The strength level of anti-delayed fracture high strength steel provided by the invention has reached 12.9 grades, 14.9 grades of use wants
It asks, the more traditional 42CrMo steel of intensity significantly improves；The corrosion resistance of steel also superior to the corrosion resistance of traditional steel, answer by satisfaction
Used in the bolt strength of bridge improve anti-delayed fracture performance do not reduce, high intensity while the performance requirement with weatherability.
Although above-described embodiment is made that detailed description to the present invention, it is only a part of the embodiment of the present invention,
Rather than whole embodiments, people can also obtain other embodiments under the premise of without creativeness according to the present embodiment, these
Embodiment belongs to the scope of the present invention.
Claims (9)
1. a kind of anti-delayed fracture high strength steel, which is characterized in that chemical constituent mass content are as follows: C 0.35~0.45%, Si
0.25~0.64%, Mn 0.30~0.90%, Cr 0.90~1.30%, Mo 0.25~0.45%, V 0.25~0.45%,
Nb 0.02~0.06%, Cu 0.2~0.5%, Ni0.2~1.0%, Als 0.02~0.05%, P≤0.015%, S≤
0.010%, N≤0.005%, surplus Fe；
The preparation step of the anti-delayed fracture high strength steel and the technical parameter of control are as follows:
(1) provide include above-mentioned chemical component molten steel, the molten steel is refined, then will refining after molten steel successively into
Capable casting is cooled down and is stripped off the skin, and obtains slab free of surface defects；
(2) it is kept the temperature after the slab of step (1) being heated 1200~1250 DEG C, the time of heat preservation is 120~240min, then
It is successively rolled, sum aggregate of spinning volume, obtains wire rod；
The rolling includes roughing and finish rolling；The temperature of roughing is 1100~1200 DEG C, and the temperature of finish rolling is 1000~1100 DEG C；
The temperature of spinning is 880~950 DEG C；The temperature of collection volume is 500~550 DEG C；
(3) wire rod of the step (2) is successively quenched and is tempered, obtain anti-delayed fracture high strength steel；
The temperature of the quenching is 900~950 DEG C, and the soaking time of quenching is 60~90min；
The temperature of the tempering is 600~650 DEG C, and the soaking time of tempering is 60~120min.
2. anti-delayed fracture high strength steel as described in claim 1, which is characterized in that the anti-delayed fracture high strength steel
Crystallite dimension is 5~8 μm.
3. anti-delayed fracture high strength steel as claimed in claim 1 or 2, which is characterized in that the anti-delayed fracture is high-intensitive
Yield strength >=1080MPa of steel, tensile strength >=1200MPa, delayed fracture stress ratio >=0.7.
4. a kind of preparation method of any one of claims 1 to 3 anti-delayed fracture high strength steel, which is characterized in that technique
Step and the technical parameter of control are as follows:
(1) provide include above-mentioned chemical component molten steel, the molten steel is refined, then will refining after molten steel successively into
Capable casting is cooled down and is stripped off the skin, and obtains slab free of surface defects；
(2) it is kept the temperature after the slab of step (1) being heated 1200~1250 DEG C, the time of heat preservation is 120~240min, then
It is successively rolled, sum aggregate of spinning volume, obtains wire rod；
The rolling includes roughing and finish rolling；The temperature of roughing is 1100~1200 DEG C, and the temperature of finish rolling is 1000~1100 DEG C；
The temperature of spinning is 880~950 DEG C；The temperature of collection volume is 500~550 DEG C；
(3) wire rod of the step (2) is successively quenched and is tempered, obtain anti-delayed fracture high strength steel；
The temperature of the quenching is 900~950 DEG C, and the soaking time of quenching is 60~90min；
The temperature of the tempering is 600~650 DEG C, and the soaking time of tempering is 60~120min.
5. preparation method as claimed in claim 4, which is characterized in that the temperature of step (1) refining is 1520~1550 DEG C, institute
The time for stating refining is 20~60min.
6. preparation method as described in claim 4 or 5, which is characterized in that the mode of step (1) refining includes vacuum refining,
The time of vacuum refining is 20~30min.
7. preparation method as claimed in claim 4, which is characterized in that the mode cast in step (1) includes continuous casting, continuous casting
Period is 25~28min.
8. preparation method as claimed in claim 4, which is characterized in that in step (1) cooling speed be 2.5~3.0 DEG C/
Min, cooling outlet temperature≤300 DEG C.
9. preparation method as claimed in claim 4, which is characterized in that the temperature of step (2) finish rolling passes through water-cooled cooling.
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| CN114908302B (en) * | 2022-05-20 | 2023-04-28 | 钢铁研究总院有限公司 | Hydrogen embrittlement resistant high-strength spring steel and heat treatment method thereof |
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| JP2006045670A (en) * | 2004-07-05 | 2006-02-16 | Nippon Steel Corp | High strength heat treated steel having excellent delayed fracture resistance and production method therefor |
| JP2007031736A (en) * | 2005-07-22 | 2007-02-08 | Nippon Steel Corp | Method for manufacturing high strength bolt excellent in delayed fracture resistance |
| CN101346481A (en) * | 2005-12-26 | 2009-01-14 | Posco公司 | High-strength steel bolt having excellent resistance for delayed fracture and method for producing the same |
| CN108070796A (en) * | 2017-11-28 | 2018-05-25 | 燕山大学 | A kind of anti-delayed fracture 1040MPa grades of weather-proof bolts |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006045670A (en) * | 2004-07-05 | 2006-02-16 | Nippon Steel Corp | High strength heat treated steel having excellent delayed fracture resistance and production method therefor |
| JP2007031736A (en) * | 2005-07-22 | 2007-02-08 | Nippon Steel Corp | Method for manufacturing high strength bolt excellent in delayed fracture resistance |
| CN101346481A (en) * | 2005-12-26 | 2009-01-14 | Posco公司 | High-strength steel bolt having excellent resistance for delayed fracture and method for producing the same |
| CN108070796A (en) * | 2017-11-28 | 2018-05-25 | 燕山大学 | A kind of anti-delayed fracture 1040MPa grades of weather-proof bolts |
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